function Pager(tableName, itemsPerPage) {
	this.tableName = tableName;
	this.itemsPerPage = itemsPerPage;
	this.currentPage = 1;
	this.pages = 0;
	this.inited = false;

	this.showRecords = function(from, to) {
		var rows = document.getElementById(tableName).rows;
		// i starts from 1 to skip table header row
		for ( var i = 1; i < rows.length; i++) {
			if (i < from || i > to)
				rows[i].style.display = 'none';
			else
				rows[i].style.display = '';
		}
	}

	this.showPage = function(pageNumber) {
		if (!this.inited) {
			alert("Error 1 !");
			return;
		}

		var oldPageAnchor = document.getElementById('pg' + this.currentPage);
		oldPageAnchor.className = 'pg-normal';

		this.currentPage = pageNumber;
		var newPageAnchor = document.getElementById('pg' + this.currentPage);
		newPageAnchor.className = 'pg-selected';

		var from = (pageNumber - 1) * itemsPerPage + 1;
		var to = from + itemsPerPage - 1;
		this.showRecords(from, to);
	}

	this.prev = function() {
		if (this.currentPage > 1)
			this.showPage(this.currentPage - 1);
	}

	this.next = function() {
		if (this.currentPage < this.pages) {
			this.showPage(this.currentPage + 1);
		}
	}

	this.init = function() {
		var rows = document.getElementById(tableName).rows;
		var records = (rows.length - 1);
		this.pages = Math.ceil(records / itemsPerPage);
		this.inited = true;
	}

	this.showPageNav = function(pagerName, positionId) {
		if (!this.inited) {
			alert("Error 2 !");
			return;
		}
		var element = document.getElementById(positionId);

		var pagerHtml = '<span onclick="'
				+ pagerName
				+ '.prev();" class="pg-normal" style="size:12px;" onmouseover="this.style.cursor=\'pointer\'"> &#171 Anterior </span> | ';
		for ( var page = 1; page <= this.pages; page++)
			pagerHtml += '<span id="pg'
					+ page
					+ '" class="pg-normal" onclick="'
					+ pagerName
					+ '.showPage('
					+ page
					+ ');"  style="size:12px;" onmouseover="this.style.cursor=\'pointer\'">'
					+ page + '</span> | ';
		pagerHtml += '<span onclick="'
				+ pagerName
				+ '.next();" class="pg-normal" style="size:12px;" onmouseover="this.style.cursor=\'pointer\'"> Siguiente &#187;</span>';

		element.innerHTML = pagerHtml;
	}
}
